Through the combination of wireless telephony and mobile computing technologies, digital wireless handsets are now available that can allow users to communicate with others by voice, e-mail, paging, facsimile, etc., and to transmit or receive information through the internet over a wireless network. Manufacturers of internet-capable telephones and personal digital assistants (PDA's) are coordinating with internet web site content providers to develop specialized versions of popular web sites for wireless access and interaction. In almost any location, while stationary or while in motion, consumers can use wireless networks to browse the world-wide web, participate in e-commerce transactions, join others through interactive game software, or communicate with others by voice or by other means through transmission of data.
In cellular communications over circuit-switched wireless networks, a link is established through radio signals over channels between a mobile transmitter/receiver and a nearby cell tower. Circuit-switched networks maintain a continuing or dedicated connection throughout the duration of a communication. This is known to be inefficient for “bursty” type communications, because the dedicated lines occupy the limited bandwidth in the network for the duration of the communication, even during periods of time when information signals are not being transmitted. The circuit-switched protocol is also inefficient for voice communications, because there are gaps of silence in most voice communications in which no signal needs to be transmitted.
In packet switched networks, data is divided into ‘envelopes’ of information that contain address, error checking, and user data. If a data communication is not continuous, as is typically the case, the communications link can be occupied by packets from other communications during the periods of downtime. In a packet switched wireless network, information is transmitted to and from mobile transmitter/receivers through radio signals in the format of discrete packets, instead of through a continuous communications link. The packets are assembled together when received to reconstruct the communication, which is a “transaction.” Therefore, portions of multiple different data communications can be transmitted along the same communications link, instead of waiting for one communication to end before another can begin.
For wireless communications, a bottleneck occurs during busy periods that can slow down communications because there are a limited number of access points into the wireless network. When a packet switched wireless network is operating near capacity, the mobile transmitters/receivers may have to wait before sending or receiving packets for communications. While a transmission delay may not be significant for an e-mail communication or a file transfer, the delay is probably not acceptable for voice-over-IP telephony or other time-sensitive communications. Accordingly, problems exist when sending or receiving urgent data over packet switched wireless networks during busy periods of network congestion.